1. Field of the Invention
The present invention relates to a glass run for automobile which is mounted along an inner part of a door frame of a vehicle door to guide a window glass which moves up and down within the door frame.
2. Related Art
As shown in FIG. 3, a glass run 110 for an automobile is mounted along an inner part of a door frame 2 of a vehicle door to guide a window glass 5 which moves up and down within the door frame 2. A conventional mounting structure of the glass run is shown in FIGS. 4 and 5.
FIG. 4 is a sectional view taken along the line I-I in FIG. 3.
Conventionally, the glass run 110 is, as shown in FIG. 4, mounted in a channel 3 of the door frame 2 to guide the window glass 5 which moves up and down within the door frame 2 and to form a seal between the window glass 5 and the door frame 2. Furthermore, in the glass run 110, a top side portion, a front vertical side portion and a rear vertical side portion, which correspond to sections of the door frame 2 of the door 1, respectively, and which are provided with extruded portions 111 formed by extrusion molding, are connected together by corner portions 112 which are molded by injection molding in shape to connect the extruded portions so as to follow the shape of the door frame 2.
In addition, a seal between the door 1 and a vehicle body is made by a door weather strip 108 which is mounted along an outer periphery of the door frame 2 of the door 1 and/or an opening weather strip 109 which is mounted on a flange at a corresponding opening in the vehicle body.
The glass run 110 is, as shown in FIG. 4, provided with an exterior side wall 120, an interior side wall 130 and a bottom wall 140 which form a substantially U-shaped cross section. An exterior seal lip 126 is provided on the exterior side wall 120 so as to extend from the vicinity of a distal portion thereof into an inside of the substantially U-shaped cross section. In addition, an interior seal lip 136 is provided on the interior side wall 130 so as to extend from the vicinity of a distal portion thereof into an inside of the substantially U-shaped cross section. Furthermore, an external cover lip 124 is provided on the exterior side wall 120 so as to extend from the vicinity of a distal portion of an external outer surface thereof toward the bottom wall 140 along the exterior side wall 120. An internal cover lip 134 is provided on the interior side wall 130 so as to extend from the vicinity of a distal portion of an internal outer surface thereof toward the bottom wall 140 along the interior side wall 130.
The exterior side wall 120, the interior side wall 130 and the bottom wall 140 are inserted in the channel 3 provided in the door frame 2, and outer surfaces of the respective walls are brought into contact with an inner surface of the channel 3. A distal end portion of an outer panel 2c of the door frame 2 is inserted between the exterior side wall 120 and the external cover lip 124. A distal end of an inner panel 2d is inserted between the interior side wall 130 and the internal cover lip 134, whereby the glass run 110 is held.
The window glass 5 moves inside the substantially U-shaped cross section of the glass run 110 and is sealed and held on both sides thereof at positions which correspond to distal portions of the glass run 110 by the exterior seal lip 126 and the interior seal lip 136, respectively.
When the window glass 5 is closed, the window glass 5 of a powered window moves up within the door frame 2. An upper end of the window glass 5 is inserted in the top side portion of the glass run 110 mounted on a top side section of the door frame 2 to thereby be brought into contact with the bottom wall 140. As this occurs, since the elevating motion of the window glass 5 cannot be controlled completely, the upper end of the window glass 5 comes to hit the bottom wall 140 and the channel 3 to thereby produce impact noise, which damages the comfortableness. In addition, the deformation of the bottom wall 140 when hit by the upper end of the window glass 5 is not stabilized, whereby the upper end of the window glass 5 deviates within the glass run 110 and the seal lips 126, 136 are deformed, sometimes leading to a drawback that the sealing property is deteriorated.
Due to this, in order to absorb the impact, a hollow portion is provided in the bottom wall 140 or a sponge sheet is mounted thereon (refer to, for example, JP-A-60-213524 and JP-UM-A-62-413). However, while an extrusion molding with blowing is necessary to provide the hollow portion in the bottom wall 140, in the event that the hollow portion is formed at the same time as the extrusion molding with blowing is carried out, it is difficult to hold the shape of the hollow portion, and this triggers difficulty in increasing the extruding speed, leading to a bad productivity. In addition, in the event that the sponge sheet is mounted, only a simple mounting of the sponge sheet on a back side of the bottom wall 140 cannot suffice a necessary thickness to provide a sufficient impact absorbing capability, and in case the sponge sheet having such a sufficient thickness is used, the stability of the bottom wall 140 relative to the door frame 2 is not sufficient.
In addition, while some countermeasures is tried in which a lip is provided at an inside portion of the glass run 110 which lies in the vicinity of the bottom wall 140 so that the upper end of the window glass 5 is made to come into forcible contact with the lip so as to absorb impact (refer to, for example, JP-A-2002-187432). In this event, however, the lip is caused to deform permanently after a long-time service, leading to a risk that the impact absorbing effect is deteriorated.
Furthermore, as shown in FIG. 5, there is proposed a configuration in which the thickness of the bottom wall 140 of the glass run 110 is gradually increased from the interior side wall 130 side to the exterior side wall 120 side so as to facilitate the deformation of the bottom wall 140 to absorb impact upon the collision of the upper end of the window glass 5 against the bottom wall 140 (refer to, for example, Japanese Utility Model Registration No. 2578541).
However, only the deformation of the bottom wall 140 cannot absorb the impact sufficiently. In addition, it was difficult to provide a sufficient space between the door frame 2 and the bottom wall 140 and hence, the impact absorbing capability provided thereby was not sufficient.